Outstanding Paper Award Subcommittee of Kagaku Kogaku Ronbunshu has assessed the 74 papers published in volume 40 into 2014, and the editorial board finally selected the four papers for Kagaku Kogaku Ronbunshu Paper Awards of 2014; those are the papers on “Effect of Solution Concentration on Breakup of Electro-Sprayed Droplets and Emission of Solute Ions,” “Effects of Channel Structure and Wettability on Liquid Water Transport in the Cathode of a Polymer Electrolyte Fuel Cell,” “Development of a New Apparatus for Evaluating Flowability of Particle with Poor Flow Behavior,” and “Fluid Mixing and Golden Ratio Condition.”
The effect of blade thickness of paddle and pitched-paddle impellers on power correlation was examined experimentally. The power number of the pitched-paddle impeller could be correlated with the effective blade height of the vertical projection. The power number of the paddle impeller increased with increasing blade thickness in laminar flow and decreased with increasing blade thickness in turbulent flow.
Bis(2-ethylhexyl) phosphate (HDEHP) as an acidic extractant was impregnated onto a polymer chain grafted onto a 6-nylon fiber at a density of 0.43 mol/kg-product. Neodymium and dysprosium ions loaded onto the fiber packed into a bed were separated by elution chromatography using 0.2, 0.3, and 1.5 M hydrochloric acid as an eluent. At various space velocities and loaded amounts, the HDEHP-impregnated fiber-packed bed exhibited a higher peak height and a narrower half width because of shorter diffusional mass-transfer path of ions and larger external area per volume. The leakage of HDEHP impregnated was found to be negligible.
In recent years, a new synthesis method that combines hydrothermal crystallization with a microwave (MW) heating technique has been developed for the synthesis of zeolites as well as zeolite membranes. Nevertheless, the effects of MW heating on the zeolite crystallization and the zeolite membrane formation are still unclear. In this study, SAPO-34 membranes were hydrothermally synthesized from two synthesis solutions of different concentrations using MW and conventional electric heating and the membrane formation processes were compared. The results indicated that MW heating accelerated the formation of SAPO-34 membranes regardless of the synthesis solution concentration. The effect of MW heating was particularly marked in the synthesis from dilute solution due to the rapid heating to the crystallization temperature.
Heat transfer by turbulent natural convection in a cubical enclosed rectangular container composed of heated and cooled side plates maintained at constant temperatures was studied using Particle Image Velocimetry (PIV), Laser Induced Fluorescence (LIF) and Large Eddy Simulation (LES). Water was chosen as the working fluid in order to achieve high Rayleigh number flow. The velocity field and temperature field in the container were experimentally visualized and analyzed by PIV and LIF, respectively, in order to examine the relationship between heat transfer and fluid flow. Numerical simulation was conducted with LES in order to validate the experimental results. The heat transfer coefficient obtained from the experimental results was found to be consistent with the heat transfer correlations proposed previously. Heat transfer coefficient and fluid flow obtained from the numerical simulation were found to coincide well with the experimental results.
Ultrasonic emulsification is known to be useful in preparation of nanoemulsions, because use of surfactant can be reduced. Moreover, nanoemulsions with droplet diameters of around 100 nm can be prepared by sequential ultrasonic irradiation from low to high frequency. In this study, oil-in-water systems of toluene-water emulsions were prepared by ultrasonic emulsification and mechanical emulsification. Ultrasound emulsification was found to be more suitable than mechanical emulsification with a homogenizer. In addition, a two-step emulsification method was applied to preparation of emulsion. Crude emulsion was prepared mechanically in the first stage, and this was irradiated with ultrasound in the second stage. The droplet size of the emulsion was found to be influenced by the relationship between droplet size of the crude emulsion and ultrasonic frequency in the second stage.
In the previous research, a method to estimate gas and liquid slug lengths in a single T-shaped microreactor was developed on the basis of the fluctuating feed pressure data. In this research, an experimental study was carried out to investigate the applicability of the method to 4-parallelized T-shaped microreactors connected to manifold-type flow distributors. As a result, it was confirmed that, in every reactor, the fluctuation cycle of feed pressure was equal to the generation cycle of a pair of gas and liquid slugs, the lengths of which could be estimated accurately. In addition, it was proposed that, by using Fourier transform analysis of pressure fluctuation time series obtained at the inlet of the liquid-side flow distributor, the number of pressure sensors required for estimating all the pressure fluctuation cycles is reduced to just one. The effectiveness of the proposed method was experimentally demonstrated under both normal and abnormal conditions of the process. Furthermore, by using the proposed method and two feed flow rate sensors, it was shown that when a partial blockage occurred in a microreactor, the estimation errors in the gas and liquid slug lengths were within 5% of real values.
This study aimed to develop a lead-free sealing glass applicable to sealing of the alkali-free glass included in 4K televisions and organic light-emitting diode digital displays. The sealing glass should ideally possess the following properties: (i) free of alkali metals, (ii) low melting point, (iii) low thermal expansion and (iv) high water durability. To meet these requirements, we prepared glasses with combinations of four different metal oxides (V2O5, ZnO, TeO2 and (ZrO)2(HPO4)2) and evaluated their properties. Two types of lead- and alkali metal-free glasses (40 wt% V2O5–10 wt% ZnO–40 wt% TeO2–10 wt% (ZrO)2(HPO4)2 and 40 wt% V2O5–8 wt% ZnO–40 wt% TeO2–12 wt% (ZrO)2(HPO4)2) were found to have low melting points, low thermal expansion coefficients and high water durability. However, further reduction of their thermal expansion coefficient was necessary for successful sealing of alkali-free glass. To this end, we incorporated ZWP (Zr2(WO4)(PO4)2), a low thermal expansion ceramic filler, into the sealing glasses. This resulted in reduction of the thermal expansion coefficient and successful sealing of alkali-free glass. These results show that V2O5–ZnO–TeO2–(ZrO)2(HPO4)2 glass is promising for sealing of 4K televisions and organic light-emitting diode digital displays.
In order to obtain fundamental data for developing an efficient recovery process of valuable metals from various molten fly ashes, the volatilization behavior of lead was investigated for two types of ash during heating with and without the addition of a chlorinating agent. Changes in the chemical form of lead during heating were followed by applying a sequential leaching. Two types ash, produced from electric resistance and gasification melting furnaces, contained lead in the major forms of PbCl2, PbO and PbS. The volatilization behavior of lead depended remarkably on the composition of lead forms. PbO was the main reactant with chlorine compounds in the ash and was converted to PbCl2. Volatilization of lead began around 873 K and proceeded with the increase in temperature. When polyvinyl chloride was used as the chlorinating agent, the volatilization of lead was accelerated due to the increased formation rate of PbCl2. Though PbS was thermally stable and remained in the solid phase during heating, it could be chlorinated effectively by the addition of polyvinyl chloride.
In recent years, problems related to chemicals such as endocrine disrupters and dioxin have attracted attention, and the need for chemical substance management among chemical manufacturers has been recognized. Based on a case study, this paper proposes and instance model for the decision-making process in a company where the safety of a product is suspected. It was found that a company's decision-making is based on the requirements of stakeholders, legal regulations, company policy (environmental management) and future prediction (regulations and market trends).